Toner material and compositions of a polymeric organic-silicon dye

ABSTRACT

AN ELECTROSCOPIC TONER FOR USE IN DEVELOPING ELECTROSTATIC CHARGE PATTERNS IS COMPRISED OF FREE-FLOWING PARTICLES CONTAINING A POLYMERIC ORGANIC-SILICON DYE HAVING A BIVALENT DIAMINOANTHRAQUINONE MOIETY IN THE RECURRING UNIT. THE TONER CAN CONTAIN FROM 0 TO ABOUT 95% BY WEIGHT OF A COLORLESS POLYMERIC BINDER MATERIAL. DEVELOPER COMPOSITIONS CAN BE FORMED USING FROM ABOUT 1 TO ABOUT 10% BY WEIGHT OF THIS TONER MIXED WITH FROM ABOUT 90 TO ABOUT 99% BY WEIGHT OF CARRIER GRANULES, SUCH AS POWDERED IRON OR GLASS BEADS.

United States Patent 3,553,133 TONER MATERIAL AND COMPOSITIONS OF A POLYMERIC ORGANIC-SILICON DYE James R. Olson, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey N0 Drawing. Filed Oct. 1, 1969, Ser. No. 862,947 Int. Cl. (303g 9/09 US. Cl. 252-62.1 16 Claims ABSTRACT OF THE DISCLOSURE This invention relates to electrography and to toner and developer compositions useful in developing electrostatic charge patterns.

Electrophotographic elements or materials conventionally involve an electrically conducting support on which is coated a photoconductive insulating material. After overall charging such as by a corona source and an imagewise light exposure that discharges the photoconductor in the exposed areas, a latent electrostatic image remains. This latent electrostatic image, as well as latent electrostatic images produced by other techniques, can be rendered visible by treatment with an electrostatic developing composition or developer. Conventional dry developers include a carrier that can be either a magnetic material such as iron filings, powdered iron or iron oxide, or a triboelectrically changeable, non-magnetic substance like glass beads or crystals of inorganic salts such as sodium or potassium chloride. As well as the carrier, electrotatic developers also include a toner that is usually formed of a resinous material suitably colored or darkened for image viewing purposes with a colorant such as a dye or pigment, for example, carbon black.

Prior toner materials used in either cascade or magnetic brush development have required lengthy procedures for their preparation. Typical toners were prepared by dispersing a coloring material into a suitable resin binder by techniques such as melt blending. Melt blending involves melting a powdered form of a resin and mixing it with a suitable pigment. This technique is generally carried out using heated compounding rolls which serve to keep the resin in a softened state and which are useful in blending the resin and pigment. However, this technique is rather lengthy and does not always result in a uniform dispersion of the pigment. Another difiiculty is encountered when some dyes are used in forming the toner in that the color fo the dye will gradually fade upon prolonged exposure to heat and light.

Accordingly, there is a need in the art for new toners which are readily formulated, which have uniform coloring and which are resistant to heat and light fading.

It is, therefore, an object of this invention to provide new toner compositions which are easily prepared for use in developing electrostatic charge patterns.

It is another object of the invention to provide novel toner compositions which are uniformly colored.

A further object of this invention is to provide novel toner compositions having colors which are resistant to heat and light fading.

3,553,133 Patented Jan. 5, 1971 Still another object of the invention is to provide novel developer compositions for use in the developement of electrostatic latent images.

These and other objects and advantages are accomplished by the use of certain polymeric organo-silicon dyes to form toner materials useful in electrophotography. These polymeric dyes can be formed into suitable size particles and used as toners. In addition, the polymeric dyes can be readily blended with a colorless polymer. The present polymeric dyes are partially soluble in such colorless polymers and consequently, the dyes are readily dispersed therein in a uniform manner. Additionally, the color of these polymeric dyes is resistant to fading since the chromophoric unit is an integral part of the backbone of the polymeric chain.

The electroscopic toner materials of the present invention are comprised of free-flowing particles containing a polymeric organo-silicon dye having a diaminoanthraquinonylene moiety in the recurring unit as an integral part of the polymeric backbone and not as a pendant side chain. Polymeric dye compositions of this type typically have an average molecular weight ranging from about 1500 to about 25,000 and contain from about 4 to about 50 recurring units having the following struc- R and R can each be a lower alkyl radical of from 1 to 7 carbon atoms, and including substituted alkyl radicals, such as methyl, ethyl, isopropyl, butyl, pentyl, cyclohexyl, heptyl, chloromethyl, chloroethyl, etc.; a lower alkenyl radical of from 2 to 7 carbon atoms such as ethenyl, propenyl, isobutenyl, pentenyl, cyclohexenyl, etc.; or an aryl radical, including substituted aryl radicals, such as phenyl, tolyl, p-chlorophenyl, pmethoxyphenyl, etc.;

n is a positive integer of from 1 to 4; and

Q is an anthraquinonylene radical having its valence bonds, as represented in the above formula, in the 1,4- the 1,5- or the 1,8-position.

Preferred materials for use in this invention are formed of recurring units as shown in Formula I above wherein R and R are both alkyl radicals having from 1 to 4 carbon atoms or both phenyl radicals; n is a positive integer having a value of 1 or 2; and Q is an anthraquinonylene radical having the formula:

. wherein:

wherein R is a hydrogen atom or a hydroxy radical.

The polymeric dyes useful in this invention typically have a glass transition temperature (T of about 45 C. to about C. with preferred materials having a glass transition temperature of about 55 C. to about 120 C. The melting point of the dyes used herein is generally within the range of about 50 C. to about C. as

measured on a Fisher-Johns Melting point Apparatus as described, for example, by Weischerger in Technique of Organic Chemistry, vol. 1, 2nd edition, part 1, page 79. Preferred materials have a melting point in the range of about 55 C. to about 170 C. By virtue of their desirable physical properties, these polymeric dyes can function both as the colorant and as a binder.

The polymeric dyes referred to herein can be prepared by several techniques as described in copending Baptista et al., U.S. application Ser. No. 851,046, filed Aug. 18, 1969, and entitled Organosilicon Polymeric Dyes. In general, the dyes used in the present toners are prepared by melt copolymerization of various diaminoanthraquinone-containing diols with, for example, diorganodianilinosilane or diorganodichlorosilane such as dialkyl-, dialkenylor diarylanilinosilanes and the dialkyldialkenylor diaryldichlorosilanes. Exemplary of useful diaminoanthraquinone-containing diols are 1,4 bis(2 hydroxyethylamino) 1,4-bis [2- (2-hydroxyethoxy ethylamino] 1,5 bis (Z-hydroxyethylamino 1,5 -bis [2- Z-hydroxyethoxy ethylamino]-, 1,4 bis{2 [2 (2-hydroxyethoxy)ethoxy]- ethylamin}-, etc., derivatives of anthraquinone. The polymerization reaction is generally conducted at reduced pressure, for example at about 0.5 to 2.5 mm. of mercury, and at elevated temperatures, typically above about 150 C. Equimolar portions of the diol and silane are used in the reaction.

The toner materials of this invention are typically prepared by dissolving the polymeric dye in a volatile organic solvent such as dichloromethane, chloroform, etc. This solution is then sprayed through an atomizing nozzle using a substantially nonreactive gas, such as nitrogen as the atomizing agent. During atomization, the volatile solvent evaporates from the airborne droplets, producing toner particles of the appropriate size. The ultimate particle size is determined by varying the size of the atomizing nozzle and the pressure of the gaseous atomizing agent. Conventionally, particles of a diameter between about /2,u and about 25 are used, with particles between about 2n and 1 being preferred, although larger particles can be used where desired for particular development conditions or developer compositions. Spray drying techniques can also be used to form toner materials of the present organo-silicon dyes with colorless polymers. When such colorless addenda are used, both the dye and colorless polymer are dissolved in the solvent and the combined solution is then sprayed as described above.

Melt-blending techniques are also useful in preparing the toners of the present invention, particularly when the above dyes are used in conjunction with a colorless polymer. Such melt-blending procedures involve melting the polymeric dye and mixing it with a colorless polymer. The dye is partially soluble in most useful colorless polymers and thus a uniform dispersion is readily obtained. The dye and polymer can readily be melted on heated compounding rolls which are also useful to stir or otherwise blend the materials. After blending, the mixture is cooled and solidified. The resultant solid mass is then broken into small pieces and finely ground to form a free-flowing powder of toner particles. The resultant toner particles usually range in size from about A2 to about in average diameter. The term average diameter does not mean that the particles are necessarily uniformly spherical in shape. This term simply has reference to the average thickness of particles as measured along several axes. Average diameter also has reference to the approximate size of the openings in a standard sieve series which will just retain or just pass a given particle.

If it is desired to use the above polymeric dyes with a colorless polymer, a wide variety of materials can be used. Examples of suitable colorless polymers would include virtually all of the resinous materials presently used as binders in the toner art such as vinyl polymers and copolymers including polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl acetals, polyvinyl ether, polyacrylic and polymethacrylic esters, polystyrene including substituted polystyrenes; polycondensates, e.g., polyesters, such as phthalic, terephthalic and isophthalic polyesters, maleinate resins and colophony-mixed esters of higher alcohols; phenol formaldehyde resins, including modified phenol formaldehyde condensates; aldehyde resins; ketone resins polyamides; polyurethanes, etc. Moreover, chlorinated rubber and polyolefins, such as various polyethylenes, polypropylenes, polyisobutylenes, are also suitable.

The polymeric dyes above can be used to form toners of the invention having various colors and various degrees of saturation of colors depending upon the chromophoric unit contained in the polymeric dye and depending upon the concentration of the dye. In general, the present toners can be prepared using from about 5 to by weight of the above described polymeric dyes. The polymeric dyes used herein are particularly stable and are not subject to discernable hydrolysis by atmospheric moisture at room temperatures. Some of these polymeric dyes can even withstand contact with 10% aqueous base solutions for a week at a time with substantially no degradation.

The toners of this invention can be mixed with a carrier vehicle to form electrophotographic developing compositions. The carrier vehicles which can be used with the present toners to form new developer compositions can be selected from a variety of materials. Suitable carriers useful in this invention include various non-magnetic particles such as glass beads, crystals of inorganic salts such as sodium or potassium chloride, hard resin particles, metal particles, etc. In addition, magnetic carrier particles can be used in connection with this invention. Suitable magnetic carrier materials are particles of ferromagnetic materials such as iron, cobalt, nickel and alloys thereof. Other magnetic carriers that can be used are resin particles coated with a thin, continuous layer of a ferromagnetic material as disclosed in Miller, US. application Ser. No. 699,030, filed Jan. 19, 1968, and entitled Metal Shell Carrier Particles. Still other useful magnetic carriers are ferromagnetic particles overcoated with a thin, continuous layer of film-forming, alkali-soluble carboxylated polymer as disclosed in Miller, US. application Ser. No. 702,201, filed Feb. 1, 1968 and entitled Scum- Retardant Carrier Particles and Compositions Thereof. Although the present toners are intended primarily for use with dry carriers, liquid carriers can also be used to form liquid developer compositions. In forming such liquid developers, it may be necessary or desirable to add surfactants, charge control agents and other such addenda.

The toner and developer compositions of this invention can be used in a variety of ways to develop electrostatic charge patterns or latent images. Such developable charge patterns can be prepared by a number of means and can be carried on either an electrophotographic element or on a non-sensitive element such as a receiver sheet. One suitable technique involves cascading the developer composition across the electrostatic charge pattern; while another technique involves applying toner particles from a magnetic brush. This latter technique requires the use of a magnetically attractable carrier vehicle in forming the developer composition. After imagewise deposition of the toner particles, the image can be fixed by heating the toner to cause it to fuse to the substrate carrying the toner. If desired, the unfused image can be transferred to another support and then fused to form a permanent lmage.

The following examples are included for a further understanding of the invention.

EXAMPLE 1 A 3.7 gram portion of polymeric dye No. 1 in Table I (infra) is dissolved in 72 ml. of dichloromethane. The solution is then spray-dried using nitrogen gas at 10 p.s.i.g. through a pneumatic nozzle (Spraying Systems C0,, Nozzle No. 1-41). The spray-dried particles are collected in an electrostatic collector. The resultant particles are measured for their melting point ton a Fisher-Johns apparatus and found to have a melting point of about 135 to 150 C. Next, the particles are mixed with an iron carrier material consisting of small iron particles having a size that they will pass through a 60 mesh screen and be retained by a 120 mesh screen of the US. standard sieve series. The mixture comprises 3% by weight of the dye or toner particles and 97% by weight of the iron carrier. A negatively charged photoconductive element comprising a conductive support having a photoconductive layer thereon is charged and imagewise exposed to light to produce an electrostatic latent image. Next, the developer mix comprised of the toner and carrier is applied to a hand-held bar magnet to form a magnetic brush. This hand magnetic brush is then lightly contacted with the surface of the photoconductive element bearing the latent image. The magnetic brush is biased at 50 v. with respect to the conductive layer of the photoconductive element. As the brush is contacted with the latent image, the positively charged toner material transfers from the magnetic carrier particles to the negative electrostatic latent image. The resulting toned image is then transferred to a white paper receiving sheet and fixed by heating on a hot plate at about 160. A direct image of the original results which is dark blue in color and nearly neutral in appearance. Next, particles of toner as prepared above are placed in a 5% aqueous solution of sodium hydroxide for 5 days and no substantial change is seen in the color of the particles. A similar image can be obtained using a toner comprised of poly{diphenyl silylene 1,4 bis[2-(2-oxyethoxy)-ethylamino]anthraquinone}.

EXAMPLE 2 A 3.2 gram quantity of polymeric dye No. 2 of Table I is dissolved in 82 ml. of dichloromethane and a toner is prepared by spray-drying as in Example 1. The melting range as determined on a Fisher-Johns apparatus is from about 97 to about 110 C. A developer mixture is prepared and an image is developed, transferred and fixed as in Example 1. The resultant image is dark red in color and of very good quality. Prolonged exposure of the image to light at elevated temperatures causes no substantial fading of the image.

EXAMPLE 3 A 4.2 gram portion of polymeric dye N o. 3 of Table I is dissolved in 101 ml. of dichloromethane and a toner is prepared by spray-drying as in the previous examples. The melting point range of this toner is found to be from about 135 to about 155 C. A developer composition is prepared as in the preceding examples. Next, a photoconductive element is charged positively and imagewise exposed to form a positive electrostatic latent image. The resultant image is developed with the developer mixture as prepared above which results in a direct reproduction of the original. This indicates that the toner particles are changed negatively with respect to the iron carrier; whereas, the toners of the preceding examples are charged positively. It appears that the presence of the hydroxyl groups on the anthraquinone nucleus of the dye results in the tendency toward negative triboelectric charging. The color of the image from this toner is light blue.

In addition to the use of these polymeric dyes as toner materials by themselves, they can be used as soluble colorant components in other polymeric binders to form toner materials. Such mixtures of polymeric dyes with other polymeric materials are useful in controlling color saturation without any apparent significant alteration of the triboelectric behavior of the toner. The usefulness of the instant polymeric dyes in such mixtures is shown in the following examples.

6 EXAMPLE 4 A 33 gram portion of a polymerized blend of styrene, methylmethacrylate and p-aminostyrene in a monomeric 'weight ration of 50/40/ 10, respectviely, is melted by compounding on a pair of mixing rollers which are heated internally by circulating oil at a temperature of about 325 F. Next, 3.5 grams of the polymeric dye No. 4 of Table I is added to the molten terpolymer. The dye is at least partially soluble in the terpolymer material. The resultant mixture is cooled and solidified. The mixture is then ground in a fluid energy mill at an air pressure of 40 p.s.i.g. The maximum particle size of the resultant material is about 25 microns. This toner is then mixed with an iron carrier material having a particle size such that it will pass through a 60 mesh screen and be retained by a mesh screen of the US. standard sieve series. The resultant developer mixture contains about 3% by Weight of toner material with the remainder being the iron carrier. A negatively charged photoconductive element is imagewise exposed and developed with the above developer mixture and the image is transferred and fixed as in Example 1. A reddish-purple image is obtained with good sharpness and high resolution. The particles of toner all appear to be charged positively with respect to the iron carrier. That is, there is no background density which can be attributed to negatively charged particles. A microscopic examination of the toner prepared above shows each particle to be uniformly colored.

EXAMPLE 5 A 15 gram portion of the terpolymer of Example 4 and 1 gram of the polymeric dye of Example 2 are dissolved in about 500 ml. of dichloromethane. The resultant solution is spray-dried as in Example 1 using nitrogen and a pressure of 20 p.s.i.g. A developer mixture is prepared using 3% by weight of this toner on the carrier material of Example 5. A print is made as in Example 4 with a good image being obtained which is lighter in tone than that obtained in Example 2 using the pure polymeric dye.

EXAMPLE 6 A 15 gram portion of the terpolymer of Example 4 and 1 gram of polymeric dye of Example 4 are dissolved in about 500 m1. of dichloromethane. The solution is spraydried as in Example 5. Next, a developer mix is prepared and a print is developed, transferred and fixed as in Example 5. A good print is obtained giving color and density resembling that of the print of Example 4.

EXAMPLE 7 R R Q Dye No.1

1 Phenyl Phenyl 1,4-anthraqninonylene. 2 Methyl Methyl. 1,5-anthraquinonylene. 3 Phenyl Phenyl 5,8-dihydroxy-1,4-anthraquinonylene. 4 Phenyl Phenyl 1,5-anthraquinonylene.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

I claim:

1. A developer composition for use in developing electrostatic charge patterns comprising carrier material and a toner comprised of free-flowing particles containing a polymeric organo-silicon dye having a bivalent diaminoanthraquinone moiety in the recurring unit.

2. A developer composition as described in claim 1 wherein the polymeric organo-silicon dye has a molecular weight between about 1500 and about 25,000.

3. A developer composition as described in claim 1 wherein said particles have an average diameter of about /2 to about 25 microns and wherein said polymeric organo-silicon dye has a melting point of about 50 to 175 C. and a glass transition temperature of about 45 to 125 C.

4. A developer composition as described in claim 1 wherein the polymeric organo-silicon dye contains the following recurring unit:

IR and R are each selected from the group consisting of an alkyl radical of from 1 to 4 carbon atoms and a phenyl radical;

n is a positive integer of from 1 to 2; and

Q is an anthraquinonylene radical selected from the group consisting of radicals having the structure and wherein R is selected from the group consisting of a hydrogen atom and a hydroxy radical. 6. A developer composition as in claim 5 wherein the particles contain up to about 95 percent by weight of a colorless polymer.

7. A developer composition as described in claim 5 wherein the colorless polymer is a styrene polymer.

8. A developer composition as in claim 5 wherein the particles have an average diameter of from about /2 to about 25 microns.

9. A developer composition as in claim 5 wherein the particles have a glass transition temperature in the range of from about to about 120 C.

10. A developer composition as in claim 5 wherein R and R are both phenyl radicals and Q is an anthraquinonylene radical having the formula:

wherein R is selected from the group consisting of a hydrogen atom and a hydroxy radical.

11. A developer composition as in claim 5 wherein R and R are both alkyl radicals having from 1 to 4 carbon atoms and Q is a bivalent radical selected from the group consisting of 1,4- and 1,5-anthraquinonylene radicals.

12. A developer composition as in claim 11 wherein R and R are both methyl radicals.

. 13. A developer composition as in claim 1 wherein the composition comprises from about to about 99% by weight of carrier granules and from about 1 to about 10% by weight of toner particles.

. 14. A developer composition as in claim 1 wherein the carrier is comprised of magnetically attractable granules.

15. 'In an eletcrographic process wherein an electrostatic charge pattern is formed and developed, the improvement wherein said pattern is developed using the electrostatic developer composition of claim 1.

16. A developer composition for use in developing electrostatic charge patterns comprising from about 90 to 99% by weight of carrier particles and from about 1 to 10% by weight of toner particles comprising a poly- -meric organo-silicon dye having the following recurring unit:

Fl S|i-OCH2OH2NHQ,-NHCHQCH2O R wherein R and R are each selected from the group consrstrng of a phenyl radical and a methyl radical and Q 1s a bivalent radical selected from the group consisting of l ,4-anthraquinonylene, 1,5-anthraquinonylene and 5,8-d1hydroxy-1,4-anthraquinonylene radical.

References Cited UNITED STATES PATENTS 11/1952 Walkup 252-62.1

GEORGE F. LESMES, Primary Examiner I. P. BRAMMER, Assistant Examiner US. Cl. X.R.

5%? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,553,133 Dated January 5, 1971 Inventor(s) James R. Olson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 32 formula 1 f-'si -cH 0cH NH-Q-NHCH CH O 7 should read s'1 eocH cH NH- -NH-4 JH cH o) -:l

Column 8, line 3 "eletrographic" should read electrographic".

Signed and sealed this ZL th day of August 1971.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

EDWARD M.FLETGHER,JR.

Commissioner of Patents [Attesting Officer 

